Quick-connect clamp and method for using the same

ABSTRACT

This invention provides a load bearing quick-base that is applied directly to the adjustable-height slot structure of a modular frame upright that is also used ubiquitously to support adjustable-height accessory brackets. By employing a set of upper (or “first”) tabs and a set of spaced-apart, lower (or “second”) tabs, the clamp can be firmly secured to the upright&#39;s front, slot-containing face as needed at any desired height in the same manner as a shelf bracket. The clamping system provides a clamp frame adapted to support a load, such as a swing arm support, that depends therefrom. The clamp frame has a first (or “upper”) tab structure with a first tab assembly including a first tab shoulder sized and arranged to engage an interior face of the base member (such as a slotted upright) adjacent to a first slot structure on the base member. There is also provided a movable (or “lower”) tab structure that is pivotally and slidably mounted with respect to the clamp frame. This second movable tab structure includes a second tab assembly having a second tab shoulder sized and arranged to engage an interior face of the base member adjacent to a second slot structure on the base member. The second tab structure is served by a locking member, which can be a spring-loaded, rotating bale, which selectively locks the movable tab structure against movement relative to the frame so as to retain the second tab shoulder and the first tab shoulder in a fixed relationship.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to adjustable bracket systems and more particularly to heavy duty, releasable clamp for supporting items.

2. Background Information

Modular frame and bracket systems are used frequently in home, office and industrial applications for organizing storage of articles and workspaces. A common technique for supporting shelves and cabinets and other accessories at a suspended location above a floor or work surface is to provide a set of freestanding or wall-mounted uprights. The uprights are typically elongated beams having a U-shaped channel cross section or a rectangular (fully-enclosed) cross section.

In a typical shelving implementation, an upright includes slots formed in a line along the elongated length of the upright's front face. For heavy duty applications, a plurality of side-by-side lines of slots can be formed on the upright face. These slots are adapted to receive hook-shaped projections on a shelf bracket or cabinet. In general, the bracket is inserted into a desired “first” slot at an acute angle, and then rotated into a roughly perpendicular orientation with respect to the upright so that a second projection engages a “second” slot located at a predetermined spacing beneath the first slot. The hook on the bracket extends within the upright and engages the inner wall thereof above the first slot's edge, preventing the bracket from pulling out of the upright under normal loading. Because each bracket's projections engage at least two spaced-apart slots in the line of slots, misalignment of the bracket is eliminated. Also, because a large number of spaced-apart slots are usually provided to each upright, the user may adjust the height of the brackets over a wide range of possible settings.

FIG. 1 details an example of an industrial workstation 100 that employs slotted uprights 102 according to the prior art. The uprights 102 in this example are freestanding, extending above a work surface 104 that is supported on bases 106 and 108. The uprights 102 are heavy duty, rectangular cross section beams in this example. They are hollow and include through-cut slots 109 arranged in two side-by-side lines on the front face of each upright 102. These lines of slots 109 are characterized generally by the depicted parallel dashed lines 114.

As shown in FIG. 1, a shelf unit 110 is provided between two of the uprights 102. The shelf unit 110 is supported by end-mounted, triangular brackets 112 that each engages at least one of the two side-by-side sets of slots (in each upright) at an appropriate height.

Given their substantial structural strength, the uprights may support a variety of other items. For example, a computer stand 120 is mounted on the leftmost upright, while a bookstand 130 is applied to the rightmost upright. The bookstand 130 includes a movable swing arm support 132 that is pivotally mounted to a mounting base 134. The mounting base (and a similar base (not shown) on the computer stand 120) is secured to a (non-frontal) side 138 of the upright using clamps, through-bolts (as shown), or any one of a variety of secure mounting assemblies. These mounting assemblies typically require significant mechanical activity to attach to, and detach from, the upright.

It is desirable that a heavy load-bearing support such as a swing arm-mounted item be well-secured to the upright to prevent unwanted droppage of the item, which can result in damage and injury. Conventional mounting assemblies take time to mount, and are not readily adjusted for new conditions (e.g. a taller worker). An arrangement that allows relatively heavy, swing arm assemblies (and similar units) to be quickly attached to, and detached from, an upright, with needed security during attachment, is highly desirable. In addition, a mounting system that employs the front face of the upright, avoiding the need for attaching bases to the upright's side, may also be desirable, particularly where the upright is mounted on a wall in a tight space or in a recessed orientation in which all or part of the upright's side is obscured.

SUMMARY OF THE INVENTION

This invention overcomes disadvantages of the prior art by providing a load bearing quick-base clamp that is applied directly to the adjustable-height slot structure of a modular shelving upright that is also used ubiquitously to support adjustable-height shelf brackets. By employing a set of upper (or “first”) tabs and a set of spaced-apart, lower (or “second”) tabs, the clamp can be firmly secured to the upright's front, slot-containing face as needed at any desired height in the same manner as a shelf bracket. Using an inventive locking mechanism, the clamp can be firmly and quickly locked against inadvertent disengagement, ensuring that heavy and valuable items, such as displays, are not dropped. When adjustment is needed, however, the clamp can be quickly disengaged, without resort to loosening of screws or bolts, by a unique release lever or bale.

In an illustrative embodiment, the clamping system provides a clamp frame adapted to support a load, such as a swing arm support, that depends therefrom. The clamp frame has a first (or “upper”) tab structure with a first tab assembly including a first tab shoulder sized and arranged to engage an interior face of the base member (such as a slotted upright) adjacent to a first slot structure on the base member. There is also provided a movable (or “lower”) tab structure that is pivotally and slidably mounted with respect to the clamp frame. This second movable tab structure includes a second tab assembly having a second tab shoulder sized and arranged to engage an interior face of the base member adjacent to a second slot structure on the base member. Notably, the second tab structure is served by a locking member, which can be a spring-loaded, rotating bale, which selectively locks the movable tab structure against movement relative to the frame so as to retain the second tab shoulder and the first tab shoulder in a fixed relationship. In this locked orientation, the first and second tab assemblies each engage the interior face of the base member respectively adjacent to the first slot structure and the second slot structure. By moving the bale to spread its ends out of holes in the movable tab structure, a user may unlock the movable tab structure so as to allow the second tab structure to be removed from engagement with the interior face of the base member. This allows for removal of the clamp frame from the base member.

To attach the clamp to the upright or other frame member, a user unlocks the bale by spreading the ends. This can be accomplished by rotating the bale so that its sides reside in the recesses of a pair of splayed-apart spreader wings at the end of the clamp frame. This causes the bale's ends to withdraw from aligned holes in the movable tab structure, thereby allowing the movable tab structure to rotate and slide freely within the clamp frame slots on the through-pin. The first or upper tabs are inserted into the selected first slots of the upright (at a desired location thereon) while the clamp is at an acute angle relative to the upright. The shoulders are moved to underlie the interior face of the upright and the clamp frame is rotated toward the upright upon the first tabs. The unlocked movable tab structure is then manipulated by sliding and rotating so that the second or lower tabs are brought into contact with a spaced-apart set of second slots at a predetermined spacing below the first slots. The second tabs are inserted into the second slots and their shoulders are moved so as to overlie the interior of the upright. The clamp frame is then rotated into a confronting relationship with the slot-containing face of the upright so as to cause the movable tab structure to slide and rotate (via the through-pin) within the slots of the enveloping clamp frame. In a confronting orientation, the holes of the movable tab structure are again aligned with the ends of the bale. The bale may then be rotated off the spreader wings to cause the ends to spring into the holes and thereby lock the movable tab structure in place. This prevents the two sets of shoulders from moving out of interfering contact with the interior of the upright adjacent to their respective slots.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention description below refers to the accompanying drawings, of which:

FIG. 1, already described, is a perspective view of a work station having a set of bracket-supporting, slotted uprights and swing arm-mounted assemblies according to a prior art implementation,

FIG. 2 is a perspective view of a quick-connect clamp and portion of an attached swing arm shown mounted and locked relative to an upright according to an illustrative embodiment of this invention;

FIG. 3 is a frontal perspective view of the clamp of FIG. 2;

FIG. 4 is a rear perspective view of the clamp of FIG. 3;

FIG. 4A is a planar view of the bottom of the clamp in FIG. 4 with the bale in an unlocked position;

FIG. 5 is a bottom end view of the clamp of FIG. 2 in a locked position;

FIG. 6 is an exposed side view of the clamp of FIG. 2 initially engaging the upper slots of an upright for attachment thereto in an unlocked position;

FIG. 7 is a bottom end view of the clamp as shown in FIG. 6 further detailing the unlocked position;

FIG. 8 is an exposed side view of the clamp of FIG. 2 now engaging the lower slots of the upright in the unlocked position;

FIG. 9 is an exposed side view of the clamp of FIG. 2 engaging both the upper slots and the lower slots of the upright in the unlocked position, and moved into a final confronting orientation with respect to the upright;

FIG. 10 is an exposed side view of the clamp of FIG. 2 in the confronting orientation with respect to the upright, and with the locking hoop now moved into a locked position; and

FIG. 11 is an exposed bottom end view of the clamp and engaged upright as shown in FIG. 10 further detailing the locked position.

DETAILED DESCRIPTION OF AN ILLUSTRATIVE EMBODIMENT

FIG. 2 details an inventive quick-connect clamp 200 for supporting a bracket with a pivotally attached swing arm support 202. The clamp 200 is shown mounted into a selected set of slots 210 and 212 arranged in parallel left (slots 210) and right (slots 212) lines along the front face 220 of a rectangular-cross-section upright 222. This upright may be mounted against a wall or other vertical surface or may be freestanding, away from a surface as shown generally in the work station 100 of FIG. 1. Where the upright is freestanding, appropriate bases, support rods/beams and other structures (not shown) may be mounted to desired locations along the upright to enhance its stability and strength. While the particular size, scale and geometry of the clamp 200, and of the upright 222 and associated slots 210, 212 to which the clamp may be fastened, may vary widely according to this invention, one exemplary embodiment provides a clamp having a rectangular or U-channel-shaped upright formed from steel having a thickness of between approximately 1/16 and 3/16 inch. The upright can be any desired length and can have a front face width WU of at least approximately 1 inch. The maximum width can be several inches or more as the clamp 200 resides fully against the front face 220 without engaging the upright's sides 230. The sides may have a depth DB of at least approximately ½ to ¾ inch to accommodate the tabs of the clamp as will be described further below. The maximum depth of the sides can be highly variable. In one example the upright 222 has a depth DB of approximately 2½ inches. The material from which the upright is constructed is highly variable, as is the surface finish. In an exemplary embodiment, mild steel is employed, but a variety of other metals and polymers or composites may be used for some or all of the parts of the upright where such alternative materials exhibit desired holding strength while the clamp 200 is in engagement with the upright 222. The slots 210, 212 in this example are conventionally sided and spaced to afford interoperability with generic modular shelving components. In this embodiment, the slots 210, 212 have a height HS of approximately ⅝ inch and a width WS of approximately 3/16 inch. The top-to-bottom spacing SHS between slots in a given vertical line is approximately ⅜ inch. Similarly the on-center spacing SS between vertical lines 240 and 242 of respective slots 210 and 212 is approximately ⅝ to 11/16 inch. Again, these approximate stated measurements are provided by way of example only and can be widely varied in alternative embodiments.

The exemplary swing arm structure 202 includes a base 250 that is attached to the clamp 200 via an upper clevis 252 and a lower clevis 254 each having a respective circular hole that is sized to receive a cylindrical pin 260. Likewise, the clamp includes a corresponding upper clamp clevis 272 and lower clamp clevis 274 having circular holes sized to receive the pin 260. The pin 260 is provided with an enlarged head 262 that stops against the upper clevis 252. A cotter pin 264 is removably seated within a slot near the bottom of the pin below the lower clamp clevis 274 and lower clevis 254. The cotter pin 264 stops against the lower clamp clevis 274 to prevent the pin's removal. The cotter pin 254 is removable to allow the pin to be slid into and out of the clevis arrangement for attachment of the base 250 to the clamp 200, and detachment of the base 250 from the clamp 200, as desired. Note that a variety of removable clips, nuts and threaded assemblies can be employed to perform the removable stopping function of the illustrative cotter pin 264 in alternate embodiments. Notably, a nut and bolt can be substituted for the pin 260 and cotter pin 264 in an alternate embodiment. Similarly, it is expressly contemplated that the stacking order of the base devises 252 and 254 and clamp clevises 272 and 274 can be varied depending upon how the user wishes to mount the arm and the relative spacing between each set of clevises.

Due to the removability of the pin 260, a variety of supporting assemblies can be removably secured to a single type of clamp 200 as shown. Alternate assemblies may be symmetrical about the clamp (as opposed to a unidirectional extending arm 280, as shown) and may or may not swivel relative to the clamp. Note that, because the receiving holes and pin are circular, the arm assembly may freely swivel. In alternate embodiments, the cross section of the pin may be non-circular or stops may be otherwise provided, to restrict or prevent swiveling of the attached assembly.

It is expressly contemplated, in alternate embodiments that the clamp may be provided with a fixed, non-removable supporting assembly. Alternatively, the clamp may have an attachment arrangement for a supporting assembly that varies from the clevis and pin assembly as shown. In general, the term “clamp” as used herein should be taken broadly to include a variety of base structures for associated supporting assemblies within the general teachings of a slot-engaging, quick connect mechanism as will be described in detail below.

With further reference to FIGS. 3, 4, 4A, and 5, the clamp 200, without an attached load-bearing support, is shown respectively in top perspective, two bottom perspectives, and an end view. The clamp 200 includes an outer frame 310 constructed from folded sheet steel or another suitable material—the exemplary sheet steel having a thickness of approximately ⅛ to 3/16 inch. The width WF and overall length LF of the outer frame are sized proportionally to the horizontal and vertical spacing of slots. In this embodiment, the exemplary width WF is approximately 1⅛ inches and the exemplary overall length, including the below-described bale spreader wings 320, is 4¾ inches. The frame 310 includes a front face 330 and a pair of sides 332, 432 formed at right angles to the front face 330 so as to define a U-shaped channel, with an interior 410 that receives the two slot-engaging tab structures 350 and 352 according to this embodiment.

Note that the term “lengthwise” is used herein to describe generally a direction along the elongated length of the upright (typically vertical when the frame is mounted on the upright) while the term “widthwise” refers to an orthogonal direction across the front face of the upright (typically horizontal when the frame is mounted on the upright). In addition, the term “horizontal,” in reference to the clamp generally refers to a direction that is orthogonal to the lengthwise direction and directed perpendicular to the plane defined by the upright's front face.

The upper tab structure 350 is fixedly mounted within the channel 410 using welds, fasteners or another suitable attachment structure. Alternatively, the upper tab structure may be formed as a unitary part of the channel 410. It has a pair of linear sides 420 that are slightly exposed (by about 1/16 to 3/16 inch) beyond each edge 430 of the frame sides 332, 432 in this example. The uppermost end of the upper tab structure includes a pair of tabs 360 and upwardly projecting tab shoulders 362. As will be described below, the tab shoulders are each located and sized to pass through a respective upright slot, and therein confront the inner wall of the upright in an area extending above the upper edge of the respective slot. Thus, the placement of each tab shoulder depends in part on the thickness of the upright. Likewise, the thickness of each tab is set to conform generally to (typically, slightly narrower than) the width (WS) of each upright slot.

The channel interior 410 also encloses a lower tab structure 352 that is movably mounted in the channel adjacent to a lower end of the frame 330. As shown in FIGS. 3-5, the lower tab structure 352 is oriented in a final “locked” position. In this position, the lower tab structure defines a pair of linear sides 450 whose edge faces are coplanar with those of the upper tab structure 420 so that, when the clamp is locked against the front face of an upright, the edge faces of the sides 420 and 450 lie flat against the face. Below and part of the sides 450 are formed a pair of tabs 460 sized to enter respective slots spaced at a given, standard spacing (number of slots) from the slots engaged by the upper tabs 360. The lower tabs 460, both include lower tab shoulders 462. Like the upper tab shoulders 362, the lower tab shoulders 462 are sized in width and location to enter a respective slot in an upright and extend beneath the bottom edge of the slot while confronting the interior face of the upright in the locked position. As can be seen, the upper tab shoulders extend generally upwardly (or outwardly) from the clamp frame while the lower tab shoulders extend generally downwardly (also outwardly from the clamp frame) in an opposing direction of extension relative to the upper tab shoulders.

The frame sides 332, 432 each include, adjacent to the lower tab structure 352, through-cut pin slots 380, 480 (shown in phantom in FIG. 4), within which rides a respective end of a through-pin 390. In this embodiment, the slot has a length of approximately 1 inch and is approximately ⅛ to 3/16 inch in width. The pin 390 is slightly smaller in diameter than the width of the slots 380, 480 to afford the pin free sliding movement. The pin 390 is fixedly mounted to the walls of the lower tab structure 352 to avoid axial pullout. The pin may be replaced with a rivet, screw, or other means which allows sliding.

In the locked position, the free ends 490 of a generally U-shaped wire bale 492 pass through holes in the sides 332, 432 of the frame 330, and thence, through the walls of the lower tab structure (see in particular FIG. 5). The bale is constructed from spring steel or a similar wire-like material that deforms elastically with sufficient movement to allow the ends to be completely withdrawn from the holes in the lower tab structure. As discussed in detail below, the bale ends 490 are adapted to remain engaged within the holes of the frame sides 332, 432 to thereby avoid loss of the bale 492 through detachment from the clamp. The bale's ends are also circular in cross section to enable rotation within the holes in the frame and lower tab structure as needed.

Having described the structure of an exemplary clamp and a slotted upright, reference is now made to FIGS. 6 to 11, which detail the operation of attaching and locking of the clamp to an upright. As shown in FIG. 6, the clamp 200 is first moved into an acutely angled angle A1 formed between the front face 220 of the upright 222 and an axis line 666 through the devises 272 and 274, with respect to a selected set of slots. These selected slots are located at the desired height within the overall lines of slots 210 (and 212, not shown) on the front face 220 of the upright 222 at which the user wishes to locate the clamp 200. For the purposes of this description, the selected side-by-side pairs of slots into which the upper tabs 360 and lower tabs 460 of the clamp 200 are engaged are respectively termed the “upper slots” 610 and the “lower slots” 620.

After locating the upper slots 610, the user then passes the upper tabs 360 (and 362, not shown) through the upper slots 610 in an approximately orthogonal (arrow 612) orientation with respect to the upright's front face 220. In this angled position, and after the upper tabs 360 have been moved fully into the slots, the upper tab shoulders 362 are moved upwardly, approximately in line with angle A1 (arrow 614) until the horizontal upper edges 668 of the upper tabs 360 engage the upper edges 670 of the upper slots 610. The slot-residing portion (disposed between each horizontal tab end (650) and horizontal upper edge (668) are sized in length (LT) slightly smaller than the length LS of each slot 210. Hence, the slot-residing portion can be passed into the slot with little resistance while exhibiting minimal lengthwise (vertical) play once the tab is engaged in a final position in the slot. To facilitate insertion of tabs into respective slots, one end of each tab 360 and 460 is defined by an angled tab face 630 and 640, respectively. Each angled tab face 630 and 640 terminates in a respective horizontal tab end face 650 and 660, respectively, that is perpendicular to the tab shoulders 362 and 462 and (as described below) resides in line with (i.e., parallel to) the adjacent edge of its slot when the clamp is finally locked in place. The horizontal tab end is approximately 1/16 to 3/16 inch in length, roughly the same as the thickness of the upright face 222. As described further below, each angled tab face is sized and arranged to allow insertion of the tab through the selected slot, and (after moving the tab shoulders upwardly) to allow subsequent rotation of the tab into a final, locked position without interference between the tab and the adjacent edge of the slot.

Either prior to the insertion of the upper tabs 360 into the upper slots 610, or thereafter, the lower tab structure 352 should be unlocked as shown in FIG. 6. This is accomplished by rotating (curved arrow 670) the bale 492 so that its sides 672 ride onto the spreader wings 320. With reference to the end view of FIG. 7, the spreader wings include recesses 710 sized to retain the sides 672 of the bale 492 in the unlocked position. In this unlocked position, the bale ends 490 are withdrawn in an axial direction (arrows 730) from the holes (690 in FIG. 6) in the lower tab structure, allowing it to pivot freely on the pin 390 (within pin slots 380, 480) relative to the clamp frame 310.

In this embodiment, each pair of angled tab ends 630 and 640 are bent slightly inwardly toward each other along bend lines 694 (FIG. 6) to produce the bent-in appearance shown generally in FIG. 7. This allows the tabs to more fully engage the slots in a lateral, or widthwise, direction so that side-to-side play in the clamp is limited once the clamp is locked in place on the upright. By appropriately adjusting the angle of the bend, the angled tab ends will be elastically deformed upon locking, and exert a spring force against the adjacent sides of the slot. To facilitate the bend, a cut is provided along the inner facing side 696 (FIG. 6) of each angled tab end 630, 640. This may also be accomplished by other means such as embossing.

As shown in FIG. 9, once the upper tabs 360 have been fully inserted into the upper slots 610, the clamp 200 is rotated (curved arrow 810) about the tabs at an angle A3 (relative to the axis line 666) to bring the lower tab structure 352 into position for insertion of the lower tabs 460 into the selected lower slots 620. In this embodiment the lower upper slots 610 and the lower slots 620 have three sets of slots 210, 212 positioned therebetween. Thus, the user positions the lower tabs for insertion into the fourth set of slots beneath the upper slots as shown. In alternate embodiments of the clamp it is expressly contemplated that the number of slots disposed between the upper tabs and the lower tabs may be more or less than three sets.

According to FIG. 8, the lower tabs 460 are inserted through the lower slots at an approximate angle A2, as shown, through a combination of linear and rotational motions allowing the pin 390 of the lower tab structure 352 to pivot and slide in the pin slots 480 (and 380, not shown). During insertion of the clamp into the upright, the pin 390 is at the lower end of the slot 480 it travels. This end is located on the clamp frame 310 so that the lower tabs 460 may enter the lower slots without interference. Once the lower tabs 460 have entered the lower slots, the tab shoulders 462 are moved to underlie the inner face of the upright below the respective lower edges 870 of the lower slots 620 as shown.

Referencing FIG. 9, with the upper tabs 360 engaging the upper slots 610 and the lower tabs 460 engaging the lower slots 620, the clamp 200 is now rotated (curved arrow 910) to confront the front face 220 of the upright 222. In this orientation, the axis line 666 is substantially parallel to the upright front face 222. By rotating the clamp frame 310 toward the face 220 about the upper tabs 360, the lower tab structure is rotated (curved arrow 920) and slid (arrow 930) via the pin 390 and pin slots 480 (and 380, not shown) until its linear sides 450 (and upper tab structure sides 420) lay against the upright front face 220. In this position, the upper edge 670 of each upper tab 360 closely engages the upper edge of its respective upper slot. Likewise, the lower edge 950 of each lower tab 460 closely engages the lower edge 870 of its respective lower slot 620. In this manner, lengthwise (vertical) play between the clamp 200 and upright 222 is limited.

With the clamp 200 in a fully engaged and confronting orientation with respect to the upright 222, the assembly may now be locked together. As shown in FIGS. 10 and 11, the bale 492 is springingly moved out of the respective recesses 710 on the spreader wings 320 in either a forward rotational direction (curved arrow 1010 as shown). Since, in the engaged location, the holes 690 of the lower tab structure are aligned with the bale ends 490, thus the ends 490 pass freely through the holes 690 as shown particularly in FIG. 11. This provides a second fixing point (with the pin 390 being the first fixing point), preventing rotation or sliding of the lower tab structure 352 with respect to the clamp frame 310. As such, the tab shoulders 362 and 462 are firmly captured against the inner face of the upright and the upper and lower edges 940 and 950 of the tabs are in close engagement with the edges of their respective slots. Accordingly, the clamp 200 is now firmly locked to the upright 222.

Removal of the clamp 200 from the upright 222 follows the reverse order to the operational steps described above. Briefly, the bale 492 is rotated to reside on the recesses 710 of the spreader wings 320 of the clamp frame 310. This allows the lower tab structure to rotate and slide freely on its pin 390 within the pin slots 380, 480. As such, the frame can be rotated about the upper tabs 360 to position the lower tabs 460 for withdrawal from the lower slots 620. The lower tabs 460 are moved out of an interfering position with the interior face of the upright, and whence, out of the lower slots 620. The frame 310 may then be further rotated away from the upright to allow the upper tabs 360 to be slid out of interfering contact with the inner face of the upright, and whence, out of the upper slots 610. The clamp is thereby removed from the upright. It can be either refit in the same upright slots at a later time, removed entirely, or moved to a different set of slots to effect a change in clamp height/position along the upright. In any case, it should be clear from the above description of the invention that a highly versatile and easily adjustable clamping system is provided. It should also be appreciated that the illustrative clamp 200 may remain mounted to the upright while the pin 260 is removed from the devises 272 and 274 of the clamp frame 310, and the arm base 250 is swapped with another arm base or another conforming structure, thereby allowing another option for rapid change-out of load-bearing units at a given mounting height along the upright.

The foregoing has been a detailed description of an illustrative embodiment of the invention. Various modifications and additions can be made without departing from the spirit and scope thereof For example, where directional terms such as “vertical,” “horizontal,” “upper” and “lower” are used, it is expressly contemplated that such directions are provided for convention and relative comparison only, and should not be taken as an absolute indicator of direction with respect to (for example) gravity. Rather, upper and lower refer only to relative orientations along a base. In alternate exemplary implementations of the invention, the base may be upside down, wherein “upper” is beneath “lower” with respect to gravity. Further, while a double, side-by-side slot arrangement is shown and described, it is expressly contemplated that the clamp can be adapted to engage only a single line of vertical slots, with appropriate stabilizing structures that engage a face of the upright (to prevent racking of the clamp relative to the upright) in an alternate embodiment. Likewise, three or more side-by-side rows of slots may be engaged with a clamp having an appropriately modified tab structure in another alternate embodiment. Accordingly, this description is meant to be taken only by way of example and not to otherwise limit the scope of the invention. 

1. A clamping system for engaging a base member having a plurality of slots arranged in a line comprising: a clamp frame adapted to support a load that depends therefrom; a first tab assembly including a first tab shoulder sized and arranged to engage an interior face of the base member adjacent to a first slot structure on the base member; a movable tab structure pivotally and slidably mounted with respect to the clamp frame including a second tab assembly including a second tab shoulder sized and arranged to engage an interior face of the base member adjacent to a second slot structure on the base member; and a locking member selectively locking the movable tab structure against movement relative to the frame so as to retain the second tab shoulder and the first tab shoulder in a fixed relationship, each engaging the interior face of the base member respectively adjacent to the first slot structure and the second slot structure, and for unlocking the movable tab structure so as to allow the second tab structure to be removed from engagement with the interior face of the base member for removal of the clamp frame from the base member.
 2. The clamping system as set forth in claim 1 wherein the locking member comprises a wire bale having a pair of ends, each of the ends rotating within and passing through holes formed in the clamp frame and being axially movable to selectively engage, to thereby lock, and disengage, to thereby unlock, holes formed in the movable tab structure.
 3. The clamping system as set forth in claim 1 wherein the clamp frame includes spreader wings that allow the bale to be springingly spread to disengage from the holes formed in the movable tab structure when the bale is rotated thereonto.
 4. The clamping system as set forth in claim 1 wherein the plurality of slots of the base member are arranged in at least two side-by-side lines of slots and wherein the first tab structure comprises at least two first tabs on the clamp structure and wherein the second tab assembly includes at least two second tabs for respectively engaging each of at least two side-by-side first slots in the first slot structure and at least two side-by-side second slots in the second slot structure.
 5. The clamping system as set forth in claim 4 wherein each of the first tabs and each of the second tabs includes an angled tab end that allows the tab to enter a respective of the first slots and the second slots at a predetermined angle free of interference.
 6. The clamping system as set forth in claim 5 wherein each of the angled tab ends is bent so as to firmly engage a width of the respective of the first slots and the second slots.
 7. The clamping system as set forth in claim 1 wherein the clamp base includes a support for a load bearing unit extending therefrom.
 8. The clamping system as set forth in claim 7 wherein the support comprises a clevis and pin assembly that supports a swinging arm.
 9. The clamping system as set forth in claim 8 wherein the clevis and pin assembly comprises a pair of clamp clevis members formed on ends of the base member and having holes for receiving a pin that, in turn, engages base clevis members formed on the swinging arm.
 10. The clamping assembly as set forth in claim 1 wherein the clamp frame defines a U-shaped interior, the first tab comprises a first tab member fixedly attached to the interior and the movable tab member includes a pin that passes into a slot on each of opposing sides of the clamp frame so as to allow the movable tab member to rotate with respect to the slot about the pin and to slide along a predetermined length of the clamp frame between opposing limit ends of the slot.
 11. A method for quick connect and disconnect of a load-bearing clamping base with respect to a base member having a line of slot structures comprising the steps of: locating a first slot structure at a desired location on the base member from a plurality of slot structures in the line; inserting a first tab assembly located on a clamp frame through the first slot structure and moving the tab assembly so that a first tab shoulder overlies an interior face of the base member adjacent to the slot structure; rotating the clamp frame to bring a movable tab structure having a second tab assembly into contact with a second slot structure at a predetermined spacing from the first slot structure; inserting the second tab assembly through the second slot structure and slidably and rotatably moving the movable tab structure relative to the clamp frame so that a second tab shoulder overlies the interior of the base member adjacent to the second slot structure; rotating the clamp base into a confronting relationship with the base member and thereby slidably and rotatably moving the movable tab structure into a lockable orientation; and moving a locking mechanism to retain the movable tab structure against rotatable and slidable movement with respect to the clamp frame.
 12. The method as set forth in claim 11 wherein the step of moving the locking mechanism comprises axially moving ends of a bale that pass through holes in the clamp frame into aligned holes of the movable tab structure.
 13. The method as set forth in claim 12 wherein the step of axially moving includes rotating the bale off of spreader wings so as to cause the ends to springingly move axially into the aligned holes.
 14. A quick-connect clamp having tabs adapted to be received by first slots and second slots, spaced apart from the first slots, on an upright comprising: a clamp frame that supports a first pair of side-by-side tabs each with respective first tab shoulders adapted to engage an interior of the upright and that extend outwardly from the clamp frame in a first direction and a second pair of side-by-side tabs each with respective second tab shoulders that extend outwardly from the clamp frame in a second direction opposite the first direction, the second pair of side-by-side tabs being movable to allow the second tab shoulders to selectively either (1) overlie or (2) be positioned remote from an interior face of the upright, when the second pair of side-by-side tabs is positioned in the second slots, while the first pair of side-by-side tabs is positioned in the first slots with the first tab shoulders overlying the interior face of the upright.
 15. The quick-connect clamp as set forth in claim 14 further comprising a locking mechanism that selectively locks the second pair of side-by-side tabs against being movable out of the position in which the second tab shoulders overlie the interior face of the upright.
 16. The quick-connect clamp as set forth in claim 15 wherein the locking mechanism comprises a movable end that selectively engages and disengages a structure side supporting at least one tab of the second pair of side-by-side tabs.
 17. The quick-connect clamp as set forth in claim 16 wherein the end is operatively connected to a sprung bale that moves between a spread orientation and an unspread orientation.
 18. The quick-connect clamp as set forth in claim 16 wherein the structure side supports a pin that slides and rotates in a slot defined in the clamp frame. 